Soil Tillage and Windbreak Effects on Millet and Cowpea: II. Dry Matter and Grain Yield

Abstract

AbstractIn the West Africa Sahel, sand storms occurring early in the growing season may severely damage emerging crops. This study was conducted to determine the Influence of ridges and windbreaks on growth, water use and grain yield of millet, Pennisetum glaucum (L.), and cowpea, Vigna unguiculata (L.) Walp. A field trial was carried out from 1985 to 1987 on a Psammentic Paleustalf in southern Niger using 12 ha of land fallowed over the previous 5 yr. Treatments for millet and cowpea were flat and ridged soil preparation and windbreaks spaced at 6, 20, 40, and 90 m. Total annual rainfall was 558, 641, and 363 mm in the 3 yr of the experiment; onset and distribution of the rains varied. Millet total dry matter (TDM) increased as total water use Increased from 250 to 400 mm. Ridging did not change total dry matter or grain yield in millet but increased cowpea grain yield by 90 and 300 kg ha−1 in 2 of the 3 yr. Protection by windbreaks spaced 6 and 20 m apart resulted in a 48 to 90% Increase in early millet TDM and a 74 to 89% improvement of cowpea ground cover. However, these early effects were not sustained throughout the growing period. Average TDM at maturity and grain yields were similar in all windbreak spacings for millet and cowpea. Although windbreaks may not increase yields of two important Sahelian crops, they may help to stabilize longterm crop production by conserving the soil and providing additional marketable commodities if an appropriate selection is made of type of windbreak and species planted.